55 Predictive factors of infection in patients with systemic autoimmune disease on biotherapy

Abstract Introduction The increasing use of biologics in chronic inflammatory diseases is accompanied by an increased risk of infectious complications. Our objective was to determine the predictive factors for the occurrence of infection in patients on biotherapy. Methods We conducted a single-center retrospective study in an internal medicine department over a period of 14-year [2009–2022], including the records of patients treated with a biologic agent presenting at least one infectious episode. Results During the study period, 20 patients among 50 treated with biologic agent had at least one infection episode. The patient mean age was 50.8 ± 12.1 [24–76] years and the male to female ratio was 1:2. The mean age at biotherapy first use was 43 ± 12.1 [17–68] years. Infections occurred after a mean duration of 12 months [0.5–36] after the initiation of biotherapy. Eleven patients were followed for chronic inflammatory bowel disease, three patients for ankylosing spondylitis, three patients for vasculitis, two patients for rheumatoid arthritis and one patient for systemic scleroderma. Only three patients were diabetic and two had chronic pulmonary disease. Thirteen patients (65%) were treated by TNFα inhibitors and 35% with anti CD20 (Rituximab). Among TNFα inhibitors, seven infections occurred in patient treated with infliximab (41%), six with adalimumab (35%) and four with etanercept (24%). At the time of infection, half of the patients were treated by corticosteroid with a median dose of 32 mg/d [5–60] and a median duration of 11 months [2–90], while 40% of the patients were on conventional immunosuppressive therapy. The infection was severe, requiring hospitalization in eight cases (40%). A statistically significant correlation was found between the occurrence of infection and a duration of anti-TNFα treatment <6 months (p = 0.003) and history of crohn's disease (p = 004). Age >50 years at the time of biotherapy introduction did not correlate with a higher risk of infection (p = 0.7) Conclusion Screening for infections in patient treated with biologic agents must be systematic, especially at the treatment initiation, in order to ensure better compliance and efficacy of the biotherapy.


Introduction
The increasing use of biologics in chronic inflammatory diseases is accompanied by an increased risk of infectious complications. Our objective was to determine the predictive factors for the occurrence of infection in patients on biotherapy.

Methods
We conducted a single-center retrospective study in an internal medicine department over a period of 14-year [2009-2022], including the records of patients treated with a biologic agent presenting at least one infectious episode.

Results
During the study period, 20 patients among 50 treated with biologic agent had at least one infection episode. The patient mean age was 50.8 AE 12.1  years and the male to female ratio was 1:2. The mean age at biotherapy first use was 43 AE 12.1 [17-68] years. Infections occurred after a mean duration of 12 months [0.5-36] after the initiation of biotherapy. Eleven patients were followed for chronic inflammatory bowel disease, three patients for ankylosing spondylitis, three patients for vasculitis, two patients for rheumatoid arthritis and one patient for systemic scleroderma. Only three patients were diabetic and two had chronic pulmonary disease. Thirteen patients (65%) were treated by TNFa inhibitors and 35% with anti CD20 (Rituximab). Among TNFa inhibitors, seven infections occurred in patient treated with infliximab (41%), six with adalimumab (35%) and four with etanercept (24%). At the time of infection, half of the patients were treated by corticosteroid with a median dose of 32 mg/d [5-60] and a median duration of 11 months [2-90], while 40% of the patients were on conventional immunosuppressive therapy. The infection was severe, requiring hospitalization in eight cases (40%). A statistically significant correlation was found between the occurrence of infection and a duration of anti-TNFa treatment <6 months (p ¼ 0.003) and history of crohn's disease (p ¼ 004). Age >50 years at the time of biotherapy introduction did not correlate with a higher risk of infection (p ¼ 0.7) Conclusion Screening for infections in patient treated with biologic agents must be systematic, especially at the treatment initiation, in order to ensure better compliance and efficacy of the biotherapy.

Introduction
The prognosis of chronic inflammatory diseases has been transformed by the use of biologic drugs. However, there is evidence of an increased risk of infection in patients undergoing biotherapy. The objective of our study was to investigate the frequency and the severity of infections in patients on biotherapy.

Results
We identified 50 patients treated with biologic therapy among 76 patients. The patient's mean age was 48 yearsAE 12.5 [23-76] and male to female ratio (M: F) was 1 :6. The mean age at initiation of biotherapy was 41.3 AE 11.6 [17-68] years. The molecules used were TNFa inhibitors in 82% of cases, rituximab in 14% of cases and tocilizumab in 4%. Infectious complications were identified in 20 patients. Infections occurred after a mean duration of 12 months [0.5-36] after the initiation of biotherapy. They affected the skin in nine cases, the bronchopulmonary tract in seven cases, the central nervous system in four cases, the gastrointestinal tract in three cases, and the upper respiratory tract in two cases. The infection was bacterial in 16 cases (64%), viral in five cases (20%) and fungal in four cases (16%). We report five cases of tuberculosis (TB), including four cases of pulmonary TB and one case of neuro-meningeal TB. The infection was severe, requiring hospitalization in only eight cases (32%). The median duration of hospitalization was 12 days . The infectious episode led to temporary interruption of biotherapy in six cases and definitive interruption in two cases. No deaths were noted.

Conclusion
Our study confirms the increased susceptibility to infections in patients treated with biologics. These infections, often bacterial, are in the majority of cases benign. However, tuberculosis remains frequent.

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